From 6700577acb385663f959d396d32db40213f5ef46 Mon Sep 17 00:00:00 2001
From: robelsust <robelsust@gmail.com>
Date: Mon, 28 Sep 2026 00:02:13 +0600
Subject: [PATCH] Upgrade/Install: Link to Plugins page instead of Plugin
 Installer after uploading a plugin.

In Plugin_Installer_Skin::after(), remove the legacy branch directing plugin upload installs back to plugin-install.php. Plugin uploads now fall through to the default branch linking to plugins.php ("Go to Plugins page"), aligning behavior with Theme_Installer_Skin.

Also adds dedicated unit tests for Plugin_Installer_Skin covering upload, web, import, and error handling.

Props therssoftware, BusinessBloomer.
Fixes #66186.
---
 .../includes/class-plugin-installer-skin.php  |   6 -
 .../tests/admin/pluginInstallerSkin.php       | 160 ++++++++++++++++++
 2 files changed, 160 insertions(+), 6 deletions(-)
 create mode 100644 tests/phpunit/tests/admin/pluginInstallerSkin.php

diff --git a/src/wp-admin/includes/class-plugin-installer-skin.php b/src/wp-admin/includes/class-plugin-installer-skin.php
index ecfb1f7bd59b5..c330cfe5ebb29 100644
--- a/src/wp-admin/includes/class-plugin-installer-skin.php
+++ b/src/wp-admin/includes/class-plugin-installer-skin.php
@@ -152,12 +152,6 @@ public function after() {
 				self_admin_url( 'plugin-install.php' ),
 				__( 'Go to Plugin Installer' )
 			);
-		} elseif ( 'upload' === $this->type && 'plugins' === $from ) {
-			$install_actions['plugins_page'] = sprintf(
-				'<a href="%s">%s</a>',
-				self_admin_url( 'plugin-install.php' ),
-				__( 'Go to Plugin Installer' )
-			);
 		} else {
 			$install_actions['plugins_page'] = sprintf(
 				'<a href="%s" target="_parent">%s</a>',
diff --git a/tests/phpunit/tests/admin/pluginInstallerSkin.php b/tests/phpunit/tests/admin/pluginInstallerSkin.php
new file mode 100644
index 0000000000000..2317aaa7c1eff
--- /dev/null
+++ b/tests/phpunit/tests/admin/pluginInstallerSkin.php
@@ -0,0 +1,160 @@
+<?php
+
+/**
+ * Tests the `Plugin_Installer_Skin` class.
+ *
+ * @group admin
+ * @group upgrade
+ *
+ * @covers Plugin_Installer_Skin
+ */
+class Tests_Admin_PluginInstallerSkin extends WP_UnitTestCase {
+
+	/**
+	 * Loads the classes to be tested.
+	 */
+	public static function set_up_before_class() {
+		parent::set_up_before_class();
+
+		require_once ABSPATH . 'wp-admin/includes/class-wp-upgrader.php';
+		require_once ABSPATH . 'wp-admin/includes/class-plugin-upgrader.php';
+		require_once ABSPATH . 'wp-admin/includes/class-plugin-installer-skin.php';
+		require_once ABSPATH . 'wp-admin/includes/misc.php';
+	}
+
+	/**
+	 * Restores global state after each test.
+	 */
+	public function tear_down() {
+		unset( $_GET['from'] );
+		parent::tear_down();
+	}
+
+	/**
+	 * Tests that after() provides a link to the plugins page when installed via upload.
+	 *
+	 * @ticket 66186
+	 *
+	 * @covers Plugin_Installer_Skin::after
+	 */
+	public function test_after_should_link_to_plugins_page_when_installed_via_upload() {
+		$skin     = new Plugin_Installer_Skin(
+			array(
+				'type' => 'upload',
+			)
+		);
+		$upgrader = new Plugin_Upgrader( $skin );
+		$skin->set_upgrader( $upgrader );
+		$skin->result = true;
+
+		$captured_actions = array();
+		add_filter(
+			'install_plugin_complete_actions',
+			static function ( $actions ) use ( &$captured_actions ) {
+				$captured_actions = $actions;
+				return array();
+			}
+		);
+
+		$skin->after();
+
+		$this->assertArrayHasKey( 'plugins_page', $captured_actions );
+		$this->assertStringContainsString( 'plugins.php', $captured_actions['plugins_page'] );
+		$this->assertStringContainsString( 'Go to Plugins page', $captured_actions['plugins_page'] );
+		$this->assertStringNotContainsString( 'plugin-install.php', $captured_actions['plugins_page'] );
+	}
+
+	/**
+	 * Tests that after() provides a link to the plugin installer when installed from the web.
+	 *
+	 * @ticket 66186
+	 *
+	 * @covers Plugin_Installer_Skin::after
+	 */
+	public function test_after_should_link_to_plugin_installer_when_installed_from_web() {
+		$skin     = new Plugin_Installer_Skin(
+			array(
+				'type' => 'web',
+			)
+		);
+		$upgrader = new Plugin_Upgrader( $skin );
+		$skin->set_upgrader( $upgrader );
+		$skin->result = true;
+
+		$captured_actions = array();
+		add_filter(
+			'install_plugin_complete_actions',
+			static function ( $actions ) use ( &$captured_actions ) {
+				$captured_actions = $actions;
+				return array();
+			}
+		);
+
+		$skin->after();
+
+		$this->assertArrayHasKey( 'plugins_page', $captured_actions );
+		$this->assertStringContainsString( 'plugin-install.php', $captured_actions['plugins_page'] );
+		$this->assertStringContainsString( 'Go to Plugin Installer', $captured_actions['plugins_page'] );
+	}
+
+	/**
+	 * Tests that after() provides an importers page link when from is import.
+	 *
+	 * @covers Plugin_Installer_Skin::after
+	 */
+	public function test_after_should_link_to_importers_page_when_from_is_import() {
+		$_GET['from'] = 'import';
+
+		$skin     = new Plugin_Installer_Skin(
+			array(
+				'type' => 'upload',
+			)
+		);
+		$upgrader = new Plugin_Upgrader( $skin );
+		$skin->set_upgrader( $upgrader );
+		$skin->result = true;
+
+		$captured_actions = array();
+		add_filter(
+			'install_plugin_complete_actions',
+			static function ( $actions ) use ( &$captured_actions ) {
+				$captured_actions = $actions;
+				return array();
+			}
+		);
+
+		$skin->after();
+
+		$this->assertArrayHasKey( 'importers_page', $captured_actions );
+		$this->assertStringContainsString( 'import.php', $captured_actions['importers_page'] );
+		$this->assertStringContainsString( 'Go to Importers', $captured_actions['importers_page'] );
+	}
+
+	/**
+	 * Tests hide_process_failed() for folder_exists error during upload without overwrite.
+	 *
+	 * @covers Plugin_Installer_Skin::hide_process_failed
+	 */
+	public function test_hide_process_failed_should_return_true_on_folder_exists_for_upload() {
+		$skin = new Plugin_Installer_Skin(
+			array(
+				'type'      => 'upload',
+				'overwrite' => '',
+			)
+		);
+
+		$error = new WP_Error( 'folder_exists', 'Folder exists.' );
+		$this->assertTrue( $skin->hide_process_failed( $error ) );
+
+		$other_error = new WP_Error( 'other_error', 'Other error.' );
+		$this->assertFalse( $skin->hide_process_failed( $other_error ) );
+
+		$skin_web = new Plugin_Installer_Skin(
+			array(
+				'type'      => 'web',
+				'overwrite' => '',
+			)
+		);
+		$this->assertFalse( $skin_web->hide_process_failed( $error ) );
+	}
+}